Level.



PATENTED DEC. 13, 1904. P. M. WALSH.

LEVEL.

APPLIOATION FILED AUG. 14. 1903.

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PATENT Trice.

PATRICK M. WALSH, OF NEW YORK, N. Y.

LEVEL.

SPECIFICATION forming part of Letters Patent No. 777,165, dated December 13, 1904. Application filed August 14, 1903. Serial No. 169,424. (No model.)

T0 at whom it may concern.-

Be it known that I, PATRICK M. WALsI-I, a citizen of the United States, residing in the borough of Manhattan, in the city and county of New York and State of New York, have invented anew and useful Improvement in Levels, of which the following is a specification.

My present invention pertains to instruments which are commonly termed levels and which are used to indicate the angles of surfaces relatively of a horizontal plane.

The levels which are now in common use comprise two forms of construction, one of which is represented by the spirit-level, commonly so called, the other being the pendulum-level. In the former theindications as read are generally approximate only and are seldom or never exact, while in the pend ulu 1nlevel the element of friction may render an exact reading thereof an impossibility.

The object of my invention is to provide a form of level which shall possess the operative reliability of a spirit-level, free from the disturbing effects of friction, and which may be read with greater accuracy than a spiritlevel at any angle at which it may be normally placed.

In the drawings, Figure 1 is a side elevation of a level which embodies my invention. Fig. 2 is a longitudinal section thereof through the line of the zero-marks shown in Fig. 1. Fig. 3 is a central transverse vertical section taken through Fig. 1, and Figs. 4 and 5 are sections of a detail.

Reference characters are relatively the same throughout the drawings.

Referring to the drawings, a, designates the stock of a level, which has a metallic guard secured to each of its ends and is perforated and suitably recessed transversely of its central part to receive a transparent annular tube 0, which is mounted in the stock a and perforated in its periphery, so that it may receive a fluid substance such, for instance, a suit able liquid Z-which is herein indicated as exactly half filling the tube 0 and, in a conventional way, as having a red color. A plug Z:

is adapted to close the perforation in the tube 0 and to seal the latter hermetically when in position.

The face of the inner end of the plug it is cohcavely curved on a radius similar to that of the interior of the tube 0. The plug Z; is so fitted to the perforation in the tube 0 that when these members are properly assembled the interior of the tube thus closed will be of the same form and dimensions throughout, including the part of the wall thereof which is formed by the concave face of the inner end of the plug 7.. A metallic frame which is formed of the members 5 7/ may be used to retain the tube 0 in position in the stock a, being themselves held in position by the screws it 71/. The members Z) Z) of the frame have their inner edges bent, as at I) b, to conform to the contour of the curved edge of the central aperture of the stock. The stock is preferably divided longitudinally at the joint a" and the parts are readily assembled and held by the guards 2'. Suitable packing--such, for instance, as a rubber ring ('Z-- may surround the tube 0 and lie between the latter and the frame members I) 7), the tube and packing-ring being held in position by flanges e e on the plates?) 7). The latter near their inner edges are graduated in parts of a circle, asshownin Fig. 1. Suitable oifsctsf'f may be either integral with or firmly attached to a frame member 7), and headed screws 1 .r may pass through the opposite frame member 6 and may be tapped into the offsetsf'f, thus serving to bind the frame members I) .1), packing-ring (Z, and tube 0 firmly together.

The operation and advantages of my invention will be readily understood and appreciated by users thereof.

The level being properly assembled, as shown and described, will indicate with accuracy the cxact angle relatively of a horizon tal plane of any surface upon which said level is placed in a normal position. The indications are given by the position of the Iiguicll.

in the tube 0 and are read by means of the scales, which are graduated upon the frame members?) 7/. The surfaces of the liquidl will naturally attain positions upon one plane however the device may be manipulated, and that plane will naturally be horizontal, the liquid, in fact, furnishing an artificial horizon from which angles may be measured by means of the graduated scales. The particu lar shape and position of the inner end k of tube partially embraced by the inturned the plug it permits the fluid substance or liqedges of the frames; a fluid substance conuid Z to occupy exactly the same amount of tained in the ring; and a scale for indicating space in and angularly of the annular tube 0, the position of the fluid substance in the tube. 5 thereby avoiding any interference with the In testimony whereof I have signed my accuracy of the indications of the device. name to this application in the presence of I claim as new and as my invention" two subscribing witnesses.

In a device of the character described, a PATRICK M. WVALSH. stock having a central aperture with a con- IO caved edge; frames having edges fitted to the contour of said concaved edge; an annular Witnesses:

CHAS. H. DAVIDS, ETELKA DERCKS. 

